Any power supply that is recommended for Arduino and provides voltage higher than 7V and lower than 16V should work. See also Arduino's recommendations page. We recommend a 9V to 12V power supply with at least 500mA, better 1A. Most Arduino boards require a 2.1mm jack. These power supplies are usually found under "CCTV power supplies". We have tested MOVI both in the US as well as in Europe and found 60Hz vs 50Hz does not make a difference. Here is a link to a power supply we recommend.

​Can I operate MOVI on batteries instead of an AC/DC adapter?

​Yes. We have successfully operated MOVI on an Arduino Uno using a 9V block battery (or two in parallel for longer operation). AAs and AAAs work too, as long as enough of them are being used. Depending on the type, the voltages of AA and AAA batteries range from 1.2V to 1.5V per battery. Also, voltage might drop over time. Therefore we recommend using at least 5 batteries of this type, better 6. This Arduino page provides some background on this topic as well.

​Does MOVI really need an external power supply? Sometimes it works over USB.

​For proper operation, MOVI usually requires a speaker connected to Audio Out. The speaker can be mono or stereo but the signal provided by MOVI is mono. The speakers here work great. The speaker impedance should be 32 ohms, which is the standard impedance for headphones. ​The output volume can be controlled in software using the MOVI library (see Appendix B and C of the user manual). For convenience, we recommend active speakers with an amplifier and volume control. Only connect 2-conductor (mono) and 3-conductor (stereo) headphone jacks to MOVI. 4-conductor jacks, as used by many smartphones (stereo plus microphone), require an adapter. Do not connect 4 ohm or 8 ohm speakers. These require an amplifier and might damage the board! If you need to connect an 8-Ohm speaker, you need a breakout amp board such as the one on this link.

WHAT EXTERNAL MICROPHONE CAN I CONNECT TO MOVI?

​The microphone should be a headset microphone or an alternative electret microphone. This audio jack is a stereo jack but only accepts a mono signal. Connecting a device to External MicIn disables the onboard microphone automatically. Note that the signal that comes through External MicIn is not amplified. Do not connect a Line-In signal or any other signal that is pre-amplified to the microphone jack. Also, microphones that require phantom power will not work. As with the speaker port, only 2-conductor (mono) and 3-conductor (stereo) headphone jacks will work. 4-conductor jacks, as used by many smartphones (stereo plus microphone), require an adapter. Here is a link to some recommended microphones.

​I uploaded my sketch, now MOVI doesn’t react anymore, EVEN when I type commands in the Serial Monitor.

Sorry this happened. As with any digital device, there are a number of ways to make MOVI or the underlying Arduino freeze. The three most common causes are these:

MOVI is not connected to an external power supply (see question 1,2 and 3)

The sketch uses too much SRAM due to too many and/or too long sentences. This can be fixed by putting as many strings as possible into flash memory, as is described in the MOVI User Manual (Section 4), the MOVI API supports the F() macro. See also Arduino's page on that.

A command is sent to MOVI in every loop() cycle. Without exception, sending a command to MOVI inside the loop() function should only happen after catching a certain event with poll(). The only function that is save to call without an if-statement in front is poll(). Also note, that poll() returns 0 for no event. Sending any command to MOVI after no-event has the same effect.

In any case, if MOVI is hung up in this way, the easiest way to get MOVI back to life is to load one of the example programs onto the Arduino and then reset MOVI while connected to an external power supply.

MOVI's communication pins have been selected as a result of an attempt to minimize the number of shields and boards that could create a conflict. So most people should not have any problems. If interference with the USB or other shields occur, MOVI's serial communication can be remapped as explained in the MOVI User Manual (Appendix A).

​HOW DO I TRAIN OTHER LANGUAGES AND ACCENTS?

Unfortunately, MOVI currently only supports English (US), German and Spanish.

​MOVI DOESN’T SEEM TO WORK WITH MY CHILDREN, WHAT’S WRONG?

MOVI’s acoustic models have been trained on adults as training with children is inherently difficult. Therefore, MOVI works best with children over 12 years old. Because female voices change less, it sometimes works with girls younger than that.

Where CAN I find the source code for movi's Arduino Library?

The MOVI Arduino library is Open Source and is included in the download zip file. Also, the latest development version can always be checked out from GitHub. We encourage you to explore and add to it. If you decide to port it to other platforms, let us know so that we can make it available to our community of users.

Where CAN I FIND THE Source CODE for the Software on the SDCaRd?

​We are using several Open Source packages to build MOVI. The list of packages is available at the bottom of this page.

Alternatively, you can use MOVI's micro SD card and mount it on a Linux computer. But first a few words of caution!

WARNING: Every MOVI microSD card is unique because it has been factory calibrated. We strongly suggest making a backup of your card before doing anything to it. Instructions on how to backup an SD card can be found in various places, including here.If your card becomes damaged and/or unusable, you will have to contact us for arranging to return your board with the card to us for re-programing and re-calibration.

The source code of the packages used on the board can be obtained by mounting MOVI's microSD Card on a Linux computer (preferably Debian). The microSD Card has two visible partitions: The update partition "MOVI Update" and the root partition "MOVI ROOT". Mount the root partition and change to the /src directory. You will find a README file with instructions on how to download the source packages for the Debian Linux used by MOVI as well as several tar-balls for packages that are not obtainable by apt-get.

What makes a good call sign ?

A good call sign should get recognized easily but not be triggered by random conversation. You will find by experimenting that some call signs work better than others. Generally speaking (no pun intended!), a good call sign should be 3 to 4 syllables long and be sufficiently different from everyday English words to not get triggered accidentally by random conversation. For instance "Arduino" works really well (though it's not easy to say...), but so does "Computer". Two syllable words usually work mediocre, including the callsign "MOVI". Single syllable words should be avoided as most of them are within the most frequent 100 words of English.